1. Field of the Invention
The present invention relates to a lens meter capable of measuring refraction characteristics of right and left lenses of eyeglasses with two measurement optical systems, particularly to a lens meter capable of obtaining in a simple manipulation optical characteristics such as a spherical power of a pair of lens attached on a frame of eyeglasses.
2. Description of the Prior Art
Conventionally, a lens meter has been known, which has a configuration that information including: a scale drawn in a concentric circle with centering an optical center of eyeglasses; a cross target showing a measurement point of the eyeglass lens; and a measurement value of optical characteristics of the lens being inspected is displayed on a monitor screen of a display, the cross target is moved into a circle in a central area of the scale while looking at the screen, and the optical characteristics (a spherical power S, a cylindrical power C, an axial angle A, prismatic values Px, Py, an additional power ADD) of eyeglass lenses are automatically computed and measured.
In this lens meter, a main switch is turned on to display the concentric scale on the monitor screen and one of a pair of lenses of eyeglasses attached on the frame of eyeglasses is mounted on a lens receiver.
By turning on the main switch, a measurement luminous flux is projected from a measurement projection optical system to the eyeglass lens to be measured, arithmetic measurement is performed to a prismatic quantity at a transmission area of the eyeglass lens where the measurement luminous flux passes, the cross target showing the measurement point of the eyeglass lens is displayed on the monitor screen based on the prismatic quantity, and the eyeglass lens is moved along the lens receiver to make the cross target fall into the scale while looking at the monitor screen.
The optical characteristics of the eyeglass lens are measured in this manner in the conventional lens meter. When the measurement of one eyeglass lens is completed, the optical characteristics of the other eyeglass lens are measured in the same procedure.
Incidentally, the lens meter of this kind has a problem that much time is required for the measurement and the measurement is bothersome because the eyeglass lens must be mounted on the lens receiver again to measure the other eyeglass lens after measuring one eyeglass lens.
Further, although unattended store, manpower reduction and the like are considered in many eyeglasses stores, a visitor himself/herself must operate the lens meter to measure the optical characteristics of lenses of eyeglasses if the lens meter is installed in an unattended store.
However, there exists a problem that the operation of measurement by the visitor in the conventional lens meter is too complicated for the visitor.